Fwd: Re: [SEL] Silver Soldering Failure

[David Everett]

Hi Luke

Silver soldering is an acquired art.

Cleanliness is paramount.  Make sure the joint is well fluxed.  If you are worried about the
solder running outside the joint area, coat the limit of solder area with Tippex.  The solder
will not stick to the Tippex.  There needs to be a gap of a couple of thou for the solder to
penetrate the joint.  Another tip - use a triangular file to make a few channels for the solder to
run through the joint if it is a bit tight.

Do not use direct heat on the solder.  Use the heat (whether it is oxy/acetylene or propane) to
generally heat the area to be soldered.  It needs to be heated quickly.  The flux will turn to a
liquid and assuming the heated area is a dull red by then, apply the solder.  If you wait too
long, the flux breqaks down and becomes ineffective.  It should be the heat of the metal that
melts the solder, not the flame.  The solder will flash round / through the joint.  If you see a
ring of solder on the other side of the joint, you've got a good 'un.

Having said the above, there are different grades of silver solder.  Generally, the higher the
silver content, the lower the melting point.  Johnson Matthey Easy Flo 2  has a melting point of
about 618 deg.  Silver flo has a higher melting point 675 deg, I believe.  Other manufacturers
will have equivalents.  

Beware, many silver solders have cadmium and phosphorus in their make up.  You must have
sufficient ventilation to avoid possible health hazards.

It might be easier to practise on a copper joint before trying steel.  Until you are sure of the
technique on your scrap /test joints, do not attempt the real job.  

Another thing: Once the solder has set, it takes a higher temperature to remelt it than the
original melting temperature.


Best of luck with your next try.

Hope this helps.

Dave
Saudi-Arabia-On-Sea





 --- Luke Tonneberger <flywheelin at hotmail.com> wrote: 
> Hi Everybody,
> 
> Well, I tried my hand at silver soldering Saturday and didn't have any 
> success. 
> I practiced on a piece of steel.


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